just asking - " Deferred: 421 Service Temporarily Unavailable"

[#1]

hi guys it' s me again... just asking... anyone know' s why we encounter this type of problem when sending outgoing e-mail " Deferred: 421 Service Temporarily Unavailable" . thanks in advance.

[abelio]

' Deferred: 421..' error code is a standard smtp error code. It' s not FortiMail related. It means that the remote smtp server it' s not accepting your mail for a X reason; (busy server, greylisting, etc); it' s an 4XX error, so it' s a temporary error

[#3]

ahhh ic... thanks again sir.